Patterns of distribution of macro-fauna in different types of estuarine, soft sediment habitats adjacent to urban and non-urban areas

Urban development typically creates a large number of potentially interacti ng disturbances that may cause impacts on assemblages of animals and plans in estuarine habitats. We tested predictions from the general model that in tertidal areas exposed to different types of disturbances have different ty pes of assemblages of benthic macrofauna. Different parts of the Port Hacki ng Estuary (New South Wales, Australia) are exposed to varying degrees of d isturbance by human activities. We predicted that the average structure of assemblages of intertidal animals, and patterns of variability would differ between urban and non-urban areas of Port Hacking. Consistent with previou s observations from the literature, there were differences in average struc ture between urban and non-urban sandy areas. Qualitative differences betwe en abundances of individual taxa in urban and non-urban areas were generall y not consistent with previous observations. Differences between assemblage s in urban and non-urban areas were not observed in muddy sediments, nor in sediments among mangroves and seagrass. No significant differences in vari ability was observed between urban and non-urban areas. Two general models may be proposed to explain the observed differences in response to urbaniza tion in different habitats: (1) animals are exposed to different levels or combinations of disturbances in different habitats; or (2) assemblages of a nimals differ in sensitivity to disturbances among habitats. (C) 2001 Acade mic Press.